Stabilizer for robotic beating-heart surgery

ABSTRACT

Surgical methods and devices allow closed-chest surgery to be performed on a heart of a patient while the heart is beating. A region of the heart is stabilized by engaging a surface of the heart with a stabilizer without having to stop the heart. Motion of the target tissues is inhibited sufficiently to treat the target tissues with robotic surgical tools which move in response to inputs of a robotic system operator. A stabilizing surface of the stabilizer is coupled to a drive system to position the surface from outside the patient, preferably by actuators of the robotic servomechanism. Exemplary stabilizers includes a suture or other flexible tension member spanning between a pair of jointed bodies, allowing the member to occlude a coronary blood vessel and/or help stabilize the target region between the stabilizing surfaces.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of and claims the benefit ofpriority from U.S. application Ser. No. 10/864,899, filed Jun. 8, 2004,now U.S. Pat. No. 8,105,235, which is a continuation of and claims thebenefit of priority from U.S. patent application Ser. No. 10/017,641,filed Dec. 14, 2001, now U.S. Pat. No. 6,764,445, which is a divisionalof and claims the benefit of priority from U.S. patent application Ser.No. 09/436,524, filed Nov. 9, 1999, now U.S. Pat. No. 6,398,726; whichis a continuation-in-part of and claims the benefit of priority fromU.S. patent application Ser. No. 09/374,643, filed Aug. 16, 1999, nowabandoned, and U.S. patent application Ser. No. 09/436,982, filed Nov.9, 1999, now U.S. Pat. No. 6,468,265, which claims the benefit ofpriority from Provisional Application Nos. 60/109,301, filed Nov. 20,1998; 60/109,303, filed Nov. 20, 1998; 60/109,359, filed Nov. 20, 1998;and 60/150,145, filed Aug. 20, 1999; the full disclosures of which areincorporated herein by reference.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAMLISTING APPENDIX SUBMITTED ON A COMPACT DISK

Not Applicable

BACKGROUND OF THE INVENTION

This invention generally relates to surgical tools, methods, and systemsfor stabilizing, retracting, and/or inhibiting physiological movement oftissues. In a particular embodiment, the invention provides a roboticsurgical stabilizer for use during robotic surgical treatments on abeating heart.

Coronary artery disease remains the leading cause of morbidity andmortality in western societies. A number of approaches have beendeveloped for treating coronary artery disease. While lifestyle changes,endovascular approaches (such as balloon angioplasty, atherectomy, andthe like) and/or pharmaceutical treatments are often effective, in manycases it is necessary to resort to surgical procedures such as coronaryartery bypass grafting to effectively treat coronary artery disease.

Coronary artery bypass grafting procedures are commonly performed usingopen-heart techniques. These open procedures generally involve dividingthe patient's sternum and spreading the chest to provide access to theheart. The patient is placed on a heart/lung machine, which oxygenatesthe patient's blood and pumps it through the circulatory system duringthe surgical procedure. After the patient is on cardiopulmonary bypass,drugs are administered to temporarily stop the patient's heart(cardioplegia) to allow the grafting procedure to be performed.Typically, a source of arterial blood is connected to a coronary arterydownstream from an occlusion, thereby bypassing the occlusion. Thesource of blood may include the left or right internal mammary artery.

While very effective in many cases, the use of open-heart surgery toperform coronary artery bypass grafting is highly traumatic to thepatient. Thus, minimally invasive medical technique for performingcardiac surgeries have recently been proposed. These minimally invasivetechniques are generally aimed at reducing the amount of extraneoustissue which is damaged during diagnostic or surgical procedures. Thiscan effectively reduce the patient's recovery time, discomfort, andother deleterious side effects of cardiac surgery. Others have proposedtechniques and devices for performing open surgery on a heart while theheart is beating. These proposals generally involve stabilizing a regionof the heart by engaging the heart with a tool called a stabilizer.Unfortunately, the proposed techniques for both minimally invasivecardiac surgery and beating-heart cardiac surgery significantly increasethe difficulty of these already complex surgical procedures. Formationof the anastomosis (the connection between the arterial source and theoccluded artery) is quite challenging in a standard coronary arterybypass grafting procedure when the heart tissues are immobile andexposed for direct manipulation. Even skilled surgeons may find itawkward and/or time consuming to instead perform such procedure in aminimally invasive manner or while the heart is beating.

In robotically assisted surgery, the surgeon typically operates one ormore master controllers to remotely control the motion of surgicalinstruments at the surgical site. The controller may be separated frompatient by a significant distance (for example, across the operatingroom, in a different room, or in a completely different building thanthe patient). Alternatively, the surgeon's work station with thecontrollers may be positioned quite near the patient in the operatingroom. Regardless, the controller will typically include one or more handinput devices, such as a joystick, exo-skeletal gloves, or the like.

The hand input devices of the surgeon's workstation are generallycoupled to the surgical instrument by a servomechanism. Morespecifically, servomotors move a manipulator, or “slave” supporting thesurgical instrument based on the surgeon's manipulation of the handinput devices.

During a robotic surgical operation, a surgeon using a robotic surgicalsystem may employ, via the manipulator, a variety of surgicalinstruments, such as tissue graspers, needle drivers, electrosurgicalcautery probes, and the like. Each of these structures perform functionsfor the surgeon, for example, holding or driving a needle, grasping ablood vessel, dissecting, cauterizing, and/or coagulating tissue, andthe like. The surgeon and/or an assistant will mount robotic surgicalinstruments having suitable end effectors to the manipulator, and willoften pass the end effectors through cannula sleeves to an internalsurgical site, so as to treat the targeted tissues while minimizinginjury to the adjacent tissue structures.

In light of the above it would be desirable to provide improved medicaldevices, systems, and methods. It would be particularly desirable ifthese improved techniques facilitated coronary artery bypass graftingand other therapies for tissues which undergo physiological movement. Itwould further be beneficial to provide robotic tools and roboticsurgical techniques for treatment of these tissues so as to takeadvantage of the recently proposed automated systems to improve the easeand speed with which complex surgeries might be performed, whileminimizing the deleterious side effects associated with accessing and/ortemporarily inhibiting the motion of the target tissues.

BRIEF SUMMARY OF THE INVENTION

The present invention provides surgical methods and devices which allowclosed-chest surgery to be performed on a heart of a patient while theheart is beating. A region of the heart is often stabilized by engaginga surface of the heart with a stabilizer. The stabilizer can inhibit(i.e., substantially reduce) physiological motion of the stabilizedregion without having to stop the heart. While the stabilized regionwill not necessarily be absolutely still, motion of the target tissuescan be inhibited sufficiently to treat the target tissues, particularlywith robotic surgical tools which move in response to inputs of arobotic system operator. A stabilizing surface of the stabilizer willoften be coupled to a drive system to position the surface from outsidethe patient, preferably by actuators of the robotic servomechanism,although manual manipulation from outside the body to position thestabilizer is also possible. Exemplary stabilizers include one or moresutures or other flexible and/or elastic tension members spanningbetween a pair of jointed bodies, thereby allowing the member to occludea coronary blood vessel and/or help stabilize the target region betweena pair of separated stabilizing surfaces.

In a first aspect, the invention provides a tissue stabilizer for usewith a robotic surgical system to treat a target tissue within a patientbody. The robotic surgical system has a plurality of manipulators withactuators for moving surgical end effectors in response to inputs by asystem operator into an input device. The tissue stabilizer comprises ashaft having a proximal end and a distal end. A first stabilizer bodyhas a stabilizing surface adapted to engage and inhibit movement of thetarget tissue. A joint couples the distal end of the shaft to thestabilizer, and a drive system is drivingly coupled to the joint so thatthe stabilizer body can be moved relative to the shaft from outside thepatient body. The drive system may allow the stabilizer surface to bepositioned using the actuators of a manipulator.

The drive system may be remotely controlled with master controlsmanipulated by the surgeon or with a manual control outside the body andmanipulated by a surgeon's assistant at the patient's side. Preferably,a wrist assembly couples the stabilizer body to the shaft so as toprovide first and second degrees of freedom, with the degrees of freedomoften being about perpendicular lateral pivotal axes. An exemplarystabilizer includes first and second stabilizer bodies coupled togetherat a joint so that first and second stabilizing surfaces preferablyremain substantially aligned when the bodies are moved relative to eachother by the actuators of the manipulator supporting the proximal end ofthe shaft.

In another aspect, the invention provides a surgical stabilizer forinhibiting motion of a tissue at a surgical site. A surface borderingthe tissue is accessible at a surgical site. The system comprises afirst body having a first anchor and a first stabilizing surface adaptedto engage the tissue surface to inhibit motion of the tissue. A secondbody has a second anchor and a second stabilizing surface adapted toengage the tissue surface to inhibit motion of the tissue. The secondbody is moveable relative to the first body.

A flexible tension member can be attached to the first anchor and to thesecond anchor to engage the tissue between the first and secondstabilizing surfaces. Optionally, movement of the first anchor away fromthe second anchor tensions the flexible member and can urge the flexiblemember against a tissue. Alternatively, the two anchors can bepositioned relative to one another and then a flexible and/or elasticmember can be positioned around the vessel to be occluded and attachedto the already positioned anchors. This allows the flexible and/orelastic member to, for example, occlude and isolate a region of a bloodvessel between the stabilizer bodies. By, including a pair of anchors oneach body, the target region of a blood vessel may be isolated from bothupstream and downstream blood flow, greatly facilitating performing ananastomosis during a coronary artery bypass grafting procedure, or thelike.

In yet another aspect, the invention provides a surgical stabilizer forinhibiting motion of a cardiac tissue accessed via a minimally invasiveaperture, wherein a heart surface borders the cardiac tissue. Thestabilizer comprises a shaft having a proximal and a distal end. A firstelongate body extends from the distal end of the shaft. The first bodyhas a first stabilizing surface adapted to engage the heart surface toinhibit motion of the cardiac tissue. A width extends across thestabilizing surface, and the body has a thickness less than the width,with at least one lateral bend along its length. A second elongate bodyis pivotally coupled to the first body at a joint adjacent the distalend of the shaft. The second body has a second stabilizing surfaceadapted to engage the heart surface to inhibit motion of the cardiactissue. A width extends across the second stabilizing surface, with thethickness again being less than the width. The second elongate body alsohas at least one lateral bend, so that the bodies cross distally of thejoint and along the stabilizing surfaces when the bodies are in a smallprofile configuration suitable for insertion through the minimallyinvasive opening.

The bodies may each comprise one or more anchors for anchoring flexibleoccluding members and may be of different lengths to facilitateoccupying the small profile even with the anchors as part of the bodies.

In a method aspect, the invention provides a method for performing asurgical procedure at a target region of a coronary vessel on a beatingheart. The method comprises stabilizing a region of the heart byengaging first and second bodies against the heart with the regiondisposed therebetween. The target region of the coronary vessel isisolated with a flexible member extending laterally across the vesselfrom the first body to the second body. Upstream and downstreamisolation of the target region may optionally be provided by includingtwo flexible members spanning between the bodies, with the membersoptionally defined by a single continuous suture loop, tape, silastictubing, or the like, although two or more pieces of such flexiblematerial may also be used.

In another method aspect, the invention provides a method for performinga surgical procedure on a target region of a beating heart. The methodcomprises introducing a stabilizer through a body wall. Motion of thetarget region is inhibited by engaging the heart with a stabilizingsurface of the stabilizer. An end effector of a robotic surgical tool isalso introduced through the body wall. The target region of the heart istreated with the end effector while the heart is beating, and whilemotion of the target region is inhibited by the stabilizer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view of a telesurgical system and method forperforming a robotic minimally invasive surgical procedure.

FIG. 2 is a perspective view of a master control workstation and apatient-side cart having three robotic manipulator arms for use in thesystem of FIG. 1.

FIG. 3 is a perspective view of an exemplary surgical robotic tool foruse in the system of FIG. 1.

FIGS. 4 and 5 illustrate the interface drive elements of the roboticsurgical tool and robotic manipulator arms, respectively.

FIGS. 6 and 7 illustrate an exemplary wrist and drive system forpositioning end effector elements of the tool of FIG. 3.

FIGS. 8A-C illustrate alternative end effectors having surfaces forstabilizing and/or retracting tissue.

FIG. 9 is a perspective view of a preferred embodiment of the inventionshowing an exemplary tissue stabilizer end effector formed of pivotallycoupled bodies having anchors for affixing tensioned flexible members.

FIGS. 9A-D illustrate the stabilizer of FIG. 9 in a small profileconfiguration for insertion into an internal surgical site via acannula.

FIG. 9E illustrates an exemplary wrist structure for use with thestabilizer end effector of FIG. 9.

FIGS. 10A-C illustrate known tissue stabilizers.

FIG. 11 illustrates a preferred method for performing a coronary arterybypass grafting by manipulating input handles of the robotic surgicalsystem of FIG. 1 with reference to an image of the internal surgicalworksite displayed on the master controller workstation.

FIG. 12 shows a schematic view of a surgical worksite on a heart priorto a coronary artery bypass graft procedure.

FIG. 13 shows a schematic view of a surgical cardiac worksiteillustrating an arrangement of end effectors of surgical manipulatorsand an endoscope for producing a telepresence effect, and an attachmentassembly comprising a servomechanism-operated manipulator arm includinga bifurcated attachment member, with six degrees of freedom of movement,for at least partially immobilizing movement of the cardiac worksite.

FIGS. 14A and 14B illustrate a method for using the stabilizer of FIG. 9to stabilize a target region of the heart and also to isolate a targetregion of a coronary artery for anastomosis.

FIG. 14C schematically illustrates an alternative preferred arrangementof the flexible members anchored to the bifurcated stabilizer bodies toisolate the target region of a coronary artery in the method of FIGS.14A and 14B.

FIGS. 15A-D shows schematic views illustrating the use of surgicalmanipulators of the robotic surgical system of FIG. 1 to suture ananastomosis on a beating heart.

FIGS. 16 and 17 show a preferred mechanism for manually manipulating thestabilizer from outside the patient's body.

FIGS. 17A and 17B show partial schematic and cross-sectional views ofthe locking mechanism shown in FIG. 17.

FIGS. 18 and 18A show a retractor for use with the system of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, a robotic surgical system 10 includes a mastercontrol station 200 and a slave cart 300. Optionally, any of severalother additional components may be included in the surgical system toenhance the capabilities of the robotic devices to perform complexsurgical procedures. An operator O performs a minimally invasivesurgical procedure at an internal surgical site within patient P usingminimally invasive surgical instruments 100. Operator O works at mastercontrol station 200. Operator O views a display provided by theworkstation and manipulates left and right input devices. Thetelesurgical system moves surgical instruments mounted on robotic armsof slave cart 300 in response to movement of the input devices. Asdescribed in co-pending U.S. patent application Ser. No. 09/433,120,filed on Nov. 3, 1999, the full disclosure of which is incorporatedherein by reference, a selectively designated “left” instrument isassociated with the left input device in the left hand of operator O anda selectively designated “right” instrument is associated with the rightinput device in the right hand of the operator.

As described in more detail in co-pending U.S. patent application Ser.No. 09/373,678 entitled “Camera Reference Control in a MinimallyInvasive Surgical Apparatus,” filed Aug. 13, 1999 (the full disclosureof which is incorporated herein by reference) a processor of mastercontroller 200 will preferably coordinate movement of the input deviceswith the movement of their associated instruments, so that the images ofthe surgical tools, as displayed to the operator O, appear substantiallyconnected to the input devices in the hand of the operator.

Optionally, an auxiliary cart A can support one or more additionalsurgical tools 100 for use during the procedure. One tool is shown herefor the illustrative purposes only. A first assistant A1 is seated at anassistant control station 200A, the first assistant typically directingmovement of one or more surgical instruments not actively beingmanipulated by operator O via master control station 200, such as atissue stabilizer. A second assistant A2 may be disposed adjacentpatient P to assist in swapping instruments 100 during the surgicalprocedure. Auxiliary cart A may also include one or more assistant inputdevices 12 (shown here as a simple joystick) to allow second assistantA2 to selectively manipulate one or more surgical instruments whileviewing the internal surgical site via an assistant display 14.Preferably, the first assistant A1 seated at console 200A has the sameimage as the surgeon seated at console 200.

As described in U.S. patent application Ser. No. 09/433,120 filed onNov. 3, 1999, previously incorporated by reference, master controlstation 200, assistant controller 200A, cart 300, auxiliary cart 300A,and assistant display 14 (or subsets of these components) may allowcomplex surgeries to be performed by selectively handing off control ofone or more robotic arms between operator O and one or more assistants.Alternatively, operator O may actively control two surgical tools whilea third remains at a fixed position. For example, to stabilize and/orretract tissues, with the operator selectively operating the retractingor stabilizer only at designated times. In still further alternatives, asurgeon and an assistant can cooperate to conduct an operation withouteither passing control of instruments or being able to pass control ofinstruments with both instead manipulating his or her own instrumentsduring the surgery.

Although FIG. 1 depicts two surgeon consoles controlling the two cartstructures, a preferred embodiment comprises only one consolecontrolling four or more arms on two carts. The scope may optionally bemounted on the auxiliary cart, and three tissue manipulator arms may bemounted on the main cart. In some embodiments, one or more tools,particularly tissue stabilizers, may not be actively driven, insteadbeing positioned by manually actuating a drive system of the tool andthen locking the tool into position.

Referring now to FIG. 2, master control station 200 includes a viewer202 wherein an image of a surgical site is displayed in use. A support204 is provided on which the operator, typically a surgeon, can rest hisor her forearms while gripping two master controls, one in each hand.Master controls are positioned in a workspace 206 disposed inwardlybeyond support 204. When using workstation 100, the surgeon typicallysits in a chair in front of the workstation, positions his or her eyesin front of the viewer 202 and grips the master controls.

FIG. 2 shows also the surgical manipulator slave or cart 300 of thetelesurgical system. In use, cart 300 is positioned close to a patientfor surgery, and the base of the cart is caused to remain stationaryuntil the surgical procedure has been completed. Cart 300 here includesthree robotic manipulator arm assemblies 302, each manipulatorsupporting an instrument 100. More specifically, one of the robotic armassemblies supports an image capture device, such as an endoscope 306(which is coupled to display 102 of the workstation). Each of the othertwo manipulator arms supports a tissue manipulation tool 308 having asurgical end effector for treating tissue.

The robotic manipulator arms will move and articulate the surgical toolsin response to motions of the input devices at the workstation, so thatthe surgeon can direct surgical procedures at internal surgical sitesthrough minimally invasive surgical apertures. The workstation 200 istypically used within an operating room with the cart, but can bepositioned remote from the cart, even miles away. An exemplary mastercontrol input device for manipulation by the surgeon is more fullydescribed in co-pending U.S. patent application Ser. No. 09/398,507,entitled “Master Having Redundant Degrees of Freedom,” as filed on Sep.17, 1999, the full disclosure of which is incorporated herein byreference. Exemplary manipulator arms are more fully described inco-pending U.S. patent application Ser. No. 09/368,309 as filed on Aug.3, 1999, for a “Manipulator Positioning Linkage for Robotic Surgery,”(the full disclosure of which is also incorporated herein by reference),which also describes manually positionable linkages supporting themanipulators. It should be noted that a number of alternative roboticmanipulator arms might be used, including those described in U.S. Pat.No. 5,855,583, the full disclosure of which is also incorporated hereinby reference.

FIG. 3 shows the general appearance of an exemplary surgical instrument100 in greater detail. Surgical instrument 100 includes an elongatedshaft 104. A joint, preferably in the form of a wrist 106, is located ata distal end of shaft 104. A housing 108 having an interface 113 isdisposed at the proximal end of shaft 104, with the interface arrangedto releasably couple instrument 100 to the manipulator arm 308.

The structure of interface 113 can be more fully understood withreference to FIGS. 4 and 5. Manipulator arm 302 includes a carriage 312with a series of drive shafts and electrical connectors for coupling thesurgical tool to the workstation 200. To maintain a sterile environment,a drape covers the manipulator arm, and a sterile adaptor 314 is mountedto carriage 312, as more fully described in co-pending U.S. patentapplication Ser. No. 09/418,726 filed on Oct. 15, 1999, the fulldisclosure of which is incorporated herein by reference. Sterile adaptor314 includes a plurality of moveable elements such as rotatable discs316. These discs are driven by drive elements of carriage 312 anddrivingly engage a drive system of the surgical tool, here by rotatingdrive elements 111 of interface 113.

As more fully described in co-pending U.S. Patent Application Ser. No.60/116,844 filed on Jan. 22, 1999, the full disclosure of which isincorporated herein by reference, drive members 111 actuate a drivesystem of the tool so as to articulate the tool end effectors about twopivotal degrees of freedom of the wrist joint, so as to open and closebifurcated or two piece end effector structures, rotate shaft 104 aboutits axis, and the like. In the exemplary embodiment, drive members 111are coupled to pulleys which move cables within shaft 104 and whichactuate the end effector elements and pivot the end effector about thewrist joint, as can be understood with reference to FIG. 6.

The wrist mechanism will be described in greater detail with referenceto FIGS. 6 and 7. Wrist 106 is disposed at distal end 110 of shaft 104.Wrist mechanism 106 includes a wrist member 112. A proximal end of wristmember 112 is pivotally mounted in a clevis 117 at distal end 110 ofshaft 104 by means of a pivotal connection 114. Wrist member 112 canpivot in the direction of arrows 156 about pivotal connection 114.

An end effector, generally indicated by reference 102, is pivotallymounted at a distal end of wrist member 112. The end effector 102 is inthe form of, for example, a clip applier for anchoring clips during asurgical procedures, a stabilizer, a needle holder, or the like. In manyembodiments, end effector 102 has two elements 102.1 and 102.2, togetherdefining a bifurcated jaw. When a different tool is desired during asurgical procedure, the tool that is then mounted on a manipulator armmay simply be removed by detaching interface 113 from sterile adaptor314 and replacing the instrument with an alternative instrument bearingthe desired end effector, such as scissors, forceps, or the like.

End effector 102 is pivotally mounted in a clevis 119 on distal end ofwrist 112 by means of a pivotal connection 160. Elements 102.1, 102.2can be angularly displaced about pivotal connection 160 toward and awayfrom each other as indicated by arrows 162, 163, and the pivotalconnection can also be used to change the orientation of the endeffector as a whole relative to wrist member 112.

As shaft 104 is rotatably mounted on housing 108 for rotation, asindicated by arrows 159, end effector 102 has three degrees of freedomof movement relative to the associated manipulator arm 302 in additionto actuation (opening and closing in this example) of the end effector.Namely, rotation about axis 109, angular displacement as a whole aboutpivot 160, and angular displacement about pivot 114. Other wriststructures and combinations of joints also fall within the scope of thepresent invention.

The three degrees of freedom of movement of instrument 100 are primarilyorientational. This is somewhat a simplification, as movement aboutthese axes will result in some change in position of the end effector.Preferably, manipulator arms 302 will provide at least three primarilytranslational degrees of freedom for changing a position of the endeffector, thereby allowing six full degrees of freedom of the endeffector in addition to end effector actuation. The exemplarymanipulator arms provide these translational degrees of freedom bypivoting tool 100 about an insertion point into a patient body through aminimally invasive aperture along shaft 104, and by movement of the toolalong the shaft through the aperture. Both the orientational movement ofthe end effector and the translational movement of the roboticmanipulator arm can be controlled by actuators such as electrical motorsof the manipulator arm, typically in response to input from theassociated master control input device. This input will typicallycomprise a movement of the input device relative to display 102,effecting a corresponding or substantially corresponding movement of theend effector relative to the endoscope. In this specification, actuationor movement of the end effectors relative to each other in the directionof arrows 162, 163, without changing the overall orientation or centerline of the end effector 102 is not regarded as a separate degree offreedom of movement.

As described above, the end effectors may take a variety of forms toperform different functions within a surgical site. Tissue stabilizerend effectors 120 a, 120 b, and 120 c, referred to generally as tissuestabilizers 120, are illustrated in FIGS. 8A-C. Tissue stabilizers 120may have one or two end effector elements 122, the elements preferablypivotally attached to the distal end of the shaft or wrist of a surgicalinstrument and preferably moveable with respect to one another, andpreferably comprising tissue-engaging surfaces 124. The tissue-engagingsurface features optionally include protrusions, ridges, vacuum ports,or other surfaces adapted so as to inhibit movement between the engagedtissue and the stabilizer, either through pressure applied to theengaged tissue, vacuum applied to draw the tissue into an at leastpartially stabilized position, or a combination of both pressure andvacuum. The ideal tissue engaging surface will constrain and/or reducemotion of the engaged tissue in the two lateral (sometimes referred toas the X and Y) axes along the tissue-engaging surface, and thestabilizer configuration and engagement with the tissue will at leastpartially decrease motion normal to the surface. Other configurationsfor traditional stabilizers are known to those of skill in the art, suchas the Octopus II of MEDTRONIC, INC. and various HEARTPORT, INC. andCARDIOTHORACIC SYSTEMS stabilizers having multipronged and doughnutconfigurations. These manners of contacting tissue allow stabilizers 120to firmly engage a moving tissue such as a beating heart of a patientand reduce movement of the tissue adjacent the stabilizer.

To facilitate performing a procedure on the stabilized tissue, anopening 126 may be formed in an individual stabilizer element 122,and/or between independently moveable end effector elements. Asillustrated in FIG. 8B, stabilizer 120 b includes cooperating tissuegrasping surfaces 128 disposed between stabilizer end effector elements122. This allows the stabilizer to grasp tissues, providing a dualfunction robotic stabilizer/grasper tool. Stabilizer 120 b may be used,for example, as a grasper while harvesting and/or preparing an internalmammary artery (IMA) for a coronary artery bypass graft (CABG)procedure, and/or to hold the IMA during formation of the anastomosis onthe stabilized beating heart.

Referring now to FIGS. 6 and 8C, and generally for the roboticendoscopic stabilizers disclosed herein, each stabilizer may comprise anirrigation hose 125 or port 131, the port/hose preferably in fluidcommunication with a lumen integrated into the shaft of the stabilizertool The lumen is preferably of a non-crushable material, such as astainless steel or plastic hypotube, to prevent crimping or crushing bythe other internal contents of the system. While an irrigation and/oraspiration capability is particularly beneficial when incorporated intoa stabilizer, such capabilities may also be incorporated into the shaftof any robotic surgical tool, as desired, such as other manipulatorsused during beating heart surgery. The port system, comprising a lumenpreferably situated inside the shaft of the stabilizer and extending outof an aperture or port in the distal portion of the shaft, as shown inFIG. 8C, or extending to a port 131 flush with the surface of the wristmechanism, as shown in FIG. 6, may be used to perform a number of tasksduring a surgical procedure (e.g., a beating heart procedure) in whichstabilization of tissue or irrigation of the surgical site is desired.Those tasks may include removing undesired fluid from the surgical site(e.g., through suction to outside the patient's body), blowing the fluidinto some other portion of the surgical site, and/or delivering fluid(such as spray humidified carbon dioxide or saline) to clear thesurgical site of material (such as body fluids which might otherwiseinterfere with the surgeon's view.) Preferably, at least the distalportion of the port system, shown in FIG. 8C, is flexible to permitbending. The exemplary port structure will be malleable or plasticallydeformable enough that it will maintain its position for use after beingrepositioned by another robotic tool or the like.

An exemplary stabilizer end effector 400 is illustrated in FIGS. 9 and9E. Preferred stabilizer 400 generally comprises a bifurcated structurehaving first and second bodies 402, 404 coupled to each other and to anassociated tool shaft 756, wrist, wrist member 112, and the like, atstabilizer pivot 406.

Each of stabilizer bodies 402, 404 comprise an elongate plate extendingdistally from pivot 406 to a distal end 408. Each plate generally has awidth 410 which is less than its length, and thickness 412 preferablyless than its width. As can be seen in FIGS. 9B and 9C, each platepreferably bends laterally relative to its length in the direction ofits width (so that bodies 402, 404 cross distally of pivot 406 when thestabilizer is in a small profile configuration) and in the direction ofits thickness (as shown in FIG. 9C) so that tissue stabilizing surfaces414 of the bodies can engage a tissue surface without interference fromthe wrist. Although these multiple bends are preferred, to facilitatebetter delivery through smaller cannulas and better contact with theheart's surface, these bends should not be understood to limit the scopeof the present invention. Pivot 406 preferably maintains generalalignment between tissue engaging surfaces 414, and these tissueengaging surfaces will generally be adapted to inhibit relative motionbetween a tissue engaged by the body and the body surface, such aspresenting a textured, knurled, roughened, or other high frictionsurface, by including one or more vacuum ports, by comprising a highfriction material, coating, and/or adhesive, or the like.

The preferred wrist joint structure for the stabilizer 400 isschematically shown in FIG. 9E. Stabilizer end effector 400 is pivotallycoupled at pivot 406 to distal clevis structure 750, which in turn ispivotally coupled to proximal clevis 752 at pivot 754. Proximal clevis752 is constructed to allow the end effector to pivot past 90° to thelongitudinal axis of shaft 756. Preferably, the clevis 750 will pivot toat least about 110° or more. This added angular freedom of movement hasproven useful in properly positioning the stabilizer during abeating-heart surgical procedure, and can be used with any of therobotic tools disclosed herein. Pivot axes 754 and 406 are preferablysubstantially orthogonal.

As can be seen in FIGS. 9-9D, protruding anchors or cleats 416 extendaway from bodies 402, 404, with the cleats having one or more channels418 for laterally receiving a flexible member such as a suture, tape,silastic tubing, or the like, and for attaching the flexible member tothe body 402, 404 of stabilizer 400. As illustrated in FIG. 9, channels418 are preferably oriented at about 45° relative to the adjacent edgeof body 402, 404 although the angle is not critical. For this angle andtwo channel, the surgeon has a choice of how to best arrange thesilastic tubing with the channels for a particular surgical procedure.Channels 418 in each anchor 416 may be of different sizes to permitdifferent types or sizes of flexible members to be used, and more thantwo slots may be provided in each anchor. Anchors 416 with channels 418therein may present an hour glass-like shape to facilitate tying off theflexible member to the anchor. In addition, although two anchors perbody are preferred, more than two anchors per body may be included, ifdesired. Bodies 402, 404 and anchors 416 may comprise a metal, such as17-4 stainless steel, or a polymer, with the anchors optionally beingsufficiently deformable to lock the flexible members into place. When ahigh strength metal, such as stainless steel, is used, anchors 416 willpreferably be electro-polished to smooth any rough edges and avoidcutting of the flexible member.

Referring now to FIGS. 9A-D, stabilizer 400 may be configured in a smallprofile configuration for insertion into an internal surgical sitethrough a minimally invasive aperture, for example, through a cannula420. Cannula 420 will preferably have a diameter of less than one-halfinch, more preferably having an inner diameter of less than 0.4″ andideally having a diameter which tapers slightly from about 0.383″ toabout 0.343″ distally. First body 402 may be longer than second body 404so as to allow the distal ends 408 of the bodies to cross withoutinterference from cleats 416. Stabilizer 404 may have an overall lengthfrom pivot 406 to distal ends 408 of bodies 402, 404 in a range fromabout 0.75″ to about 3.50″. More preferably having a length from about1.0″ to 2.5″. The plates from which the bodies are formed may havethicknesses of about 0.035″, while anchors 416 may protrude by adistance in range from about 0.03″ to about 0.15″ with the distalanchors optionally protruding less than the proximal anchors to enhanceclearance between the stabilizer and the surrounding cannula 420, asshown best in FIG. 9C.

A wide variety of alternative stabilizer structures may also be usedwithin the scope of the present invention, including stabilizerstructures similar to those known for use in open surgical procedures.Referring now to FIGS. 10A-C, there can be seen a number of suction-typeattachment members 422, which are generally releasably held by aconduit-type attachment arm 424. Attachment arm 424 may be connected toand in communication with a suction hose which communicates with avacuum or suction source (not shown). FIG. 10A shows a circular-designattachment arm 422 having a plurality of openings 426 wherethroughsuction occurs to releasably engage the circular-design attachment arm422 to the surgical worksite. The known rigid circular-design attachmentarm 422 is often unsuitable for insertion through a relatively smallcannula because of its shape and size.

FIGS. 10B and 10C show a prior art linear design attachment member 422having a plurality of openings 426 wherethrough a suction occurs toreleasably engage the linear design attachment member 422 to thesurgical worksite. The linear design attachment member 422 of FIGS. 10Band 10C may be introduced through a cannula, but may not be capable ofsurrounding the surgical worksite. Therefore, when such a linear designattachment member 424, as illustrated in FIGS. 10B and 10C is employed,two attachment manipulators may be employed to stabilize the surgicalworksite. Alternatively, a V-shaped design attachment member capable ofbeing introduced through a cannula and expanding to surround thesurgical worksite, may include a pair of attachment jaws capable ofpivoting at a stabilizer pivot point, similar to pivot point 406 ofpreferred stabilizer 400 (see FIGS. 9 and 13) may be employed. Each ofthe attachment jaw elements may optionally include a plurality ofopenings 426 wherethrough suction occurs to releasably engage theV-shaped design attachment member to the surgical worksite. Optionally,the actuated jaws may be spring-loaded to move away from each other whenthey are clear of the cannula, but the jaws will preferably be directlycontrolled by an actuator motor of the associated manipulator arm.

Referring now to FIGS. 1 and 11, operator O may initially bemanipulating tools A and B with input devices 210L and 210R using his orher left and right hands LH and RH, respectively. When the surgeon oroperator O intends to maintain control over tool B, but wishes toreposition stabilizer 120, the operator may decouple input device 210Lfrom tool A and instead couple the input device in his or her left handLH with stabilizer 120 using the tool selection routine described inco-pending U.S. patent application Ser. No. 09/433,120 filed Nov. 3,1999 entitled “Cooperative Minimally Invasive Robotic Surgery,”previously incorporated herein by reference.

Once the selected master input device has been allowed to float, themaster may be moved into alignment with the newly selected tool. Oftenthis will occur while the surgeon keeps a hand on the input device, withactuators of the master control station moving the input device at amoderate pace and with moderate force to avoid injury to the surgeon.Master input device 210L may then be coupled to tool C (stabilizer 120in this example) while tool A is held in a fixed position. This allowsthe operator to reposition stabilizer 120 against an alternative portionof coronary artery CA. The tool selection process may be repeated toreassociate the masters with tools A and B, while tool C remains held ina fixed position by its drive system. This allows the surgeon to controlrepositioning stabilizer 120 without significantly interruptinganastomosis of the coronary artery CA with the internal mammary arteryIMA. Hence, the system may allow an operator to sequentially controlmore than two robotic tools using the operator's two hands and theservomechanism of the robotic system. In addition, the stabilizer may beprovided with a mechanism to enable the surgeon's assistant to manuallymove the stabilizer, as desired, during the surgical procedure.

The present invention is particularly useful in performing coronaryartery bypass graft (CABG) procedures without cardioplegia. ConventionalCABG procedures are described in U.S. Pat. No. 5,452,733 which is fullyincorporated herein by reference. Conventional CABG procedures ofteninvolve preparing a source of arterial blood for subsequent bypassconnection to the narrowed coronary artery at a location beyond thenarrowing. Such arterial blood sources will be primarily of two types.First, existing arteries can be dissected from their natural attachmentsand transected to provide upstream and downstream free ends. Theupstream free end, which is the arterial blood source, will be securedto the coronary artery at a location distal to the narrowing, thusproviding the desired bypass blood flow. Second, artificial arterialshunts may be prepared by attaching a natural or synthetic blood vessel,typically a length obtained from a leg vein, at one end to the proximalascending aorta and at the other end to the target location on acoronary artery. The use of transected arteries is generally preferablesince they tend to remain patent for long periods and require only oneanastomosis.

The arterial blood source will preferably be the left or right internalmammary artery. It will also be possible to use the gastroepiploicartery in the abdomen. Access to the gastroepiploic artery can beobtained laparoscopically, with the artery being brought into the thoraxfrom the abdominal cavity via a window through the diaphragm. Whennecessary, it will be possible to prepare free grafts from the aorta.Such free grafts can be formed from veins or arteries harvested fromother locations in a patient's body, or may comprise synthetic graftmaterials. The free graft may be passed into the thorax through eitheran access trocar sheath or through the aorta (by punching a holetherethrough). The free grafts thus located will be attached at one endto the proximal ascending aorta (to provide the arterial blood supply)and at the other end to the target location on the coronary artery.

The left internal mammary artery is suitable as an arterial source fortarget locations on the left anterior descending coronary artery, thediagonal coronary artery, the circumflex artery/obtuse marginal artery,and the ramus intermedius coronary artery.

The right internal mammary artery is available for connection to all ofthe same target locations, as well as the right coronary artery and theposterior descending artery. The gastroepiploic artery and free graftsfrom the aorta will be available for all target locations.

In transecting the left internal mammary artery, the left lung may bedeflated and a length of the internal mammary artery dissected from theinner thoracic wall. The side branches of the internal mammary arteryare sealed.

As shown in FIG. 12, the heart 602 will often be repositioned usingsuitable instruments in order to better expose the coronary artery 703which is the target for anastomosis in the surgical worksite 686.Suitable instruments include hooks, suction catheters, grasping rods,pushing rods, and the like. Gravity can also be used to help positionthe heart 602 if the patient can be turned appropriately. As illustratedin FIG. 12, a pair of graspers 900 and 902 may be used to secureopposite sides of the heart 602 and permit turning of the heart 602 asdesired. Optionally, trocar sheaths (not shown) may be introduced atother sites of thoracic access. For example, one or more parasternalpunctures, one or more punctures in the midclavicular line, and/or asubxyphoid puncture may be introduced.

Elastic members 904 and 906, which are introduced through appropriatelypositioned trocar sheaths (not shown), often place axial tension on thesurgical worksite 686 in the coronary artery 703 which is to be preparedfor anastomosis. In addition, they provide a bloodless lumen, permittingexcellent visualization. As illustrated in FIG. 12, the coronary artery703 is first pulled upward from the surface of the heart 602 andstretched using the pair of elastic members 904 and 906.

The surgical worksite 686 in the coronary artery 703 is designated foranastomosis. The motion of the surgical worksite 686 is preferablyinhibited by engaging a surface of heart 702 with stabilizer 120, 400.It should be understood that the stabilizer need not completely preventmotion of surgical site 686.

Referring to FIG. 13, the coronary artery bypass grafting procedure willgenerally proceed by manipulating surgical tools 100 through a body wallBW, such as the chest wall, abdominal wall, or like, while the tools areinserted through the body wall BW using cannulas 420. Manipulator 302supporting stabilizer 120 stabilizes motion of surgical worksite 686 byapplying force to the stabilizer (here with a V-shaped arrangement oflinear design attachment members 422) through downward pressure ortensioning of internal cables such that the stabilizer inhibits motionof the surgical worksite 686 in at least one direction, and ideally in aplurality of directions. As explained more fully in co-pending U.S.patent application Ser. No. 09/436,982 filed concurrently herewith, thefull disclosure of which is incorporated herein by reference, residualmotion of surgical worksite 686 may optionally be accommodated by therobotic surgical system by tracking the remaining motion and maintainingalignment between the surgical tools 100 and the movement of thesurgical worksite. Advantageously, the heart may be tolerant of theforces involved in reducing motion of the surgical worksite as comparedto attempts to completely cease motion.

As was generally described above, tools 100 may be positioned bypivoting the tools about insertion points 430 through body wall BW byaxial movement along the tool shafts through the cannulas 420, rotationof the shafts about their axes, and articulation of the tools. In someembodiments endoscope 306 may have a fixed viewing angle rather thanbeing an articulated structure as illustrated in FIG. 13.

A method for isolating a coronary artery CA downstream of an occlusionOC using preferable stabilizer 400 can be understood with reference toFIGS. 14A and 14B. Rather than straightening and tensioning coronaryartery CA by tensioning elastic flexible members through the chest wall,a flexible member 502 is passed under and around the coronary artery CAusing end effectors 102 of tools 100 as illustrated in FIG. 14A.Stabilizer 400 is positioned against heart 602 with the first and secondbodies 402, 404 of the stabilizer positioned on either side of thecoronary artery CA so as to inhibit motion of the surgical worksite. Atarget region 506 of the coronary artery CA is isolated from upstreamand downstream blood flow by tensioning flexible member 502 and tyingthe tensioned flexible members off to anchors 416 of stabilizer 400.Tying off the vessel in this manner not only permits isolation of thesurgical site, but also can help to inhibit movement of the surgicalworksite between bodies 402, 404 during beating-heart surgery.

The exemplary embodiment flexible member 502 comprises silastic tubing,the tube preferably being large enough to catch in the channels ofanchors 416 but not so large as to require large penetrations about thevessel or to be ineffective in occluding the vessel. For the exemplaryanchors 416 having a channel with a width of about 0.010 inches, apreferred silastic tubing will have an outer diameter of about 0.050″and an inner diameter of 0.030″, such as that available from QUESTMEDICAL of Allen, Tex. under the product name “Retract-O-Tape”.Alternative elastic and inelastic flexible members may also be used.Flexible member 502 is tied off to anchors 416 using tools 100 in atotally endoscopic procedure, while heart 602 is beating and without anyneed for a thoracotomy or a mini-thoracotomy.

Referring now to FIG. 14C, an alternative arrangement for occludingcoronary artery CA using preferred stabilizer 400 is illustrated. Itshould be understood that tensioning of flexible member 502 may beeffected by moving first body 402 away from second body 404 about pivot406, or the flexible member may simply be tied with tension to thepre-positioned anchor of the stabilizer using tools 100. Regardless,tension of flexible member 502 will preferably substantially occlude thelumen of coronary artery CA, and the tension may also help to inhibitmovement of the coronary tissues between first and second bodies 402,404. As shown in FIG. 14C, the tubing is preferably passed sufficientlyunder the artery CA to capture some of the heart tissue between anexterior heart all surface EHW and an interior heart wall surface IHW soas not to tear or damage either the vessel or the heart when theflexible member is pulled taught.

Referring now to FIG. 15A, the surgical worksite 86 is seen. An incision908 is made in the wall of the coronary artery 703, where the incision908 has dimensions selected to match those of the upstream free end 910(see FIG. 15B) of the internal mammary artery 600 graft. The incision908 is made by first piercing the arterial wall 912 using the tip of ascalpel (not illustrated). The surgical instrument 82 c, such as ascissor, is attached to the surgical manipulator 78. The surgical tool82 c is introduced through the incision 908 to axially extend theincision 908, as illustrated at 914 in FIG. 15B. The movement ofsurgical instrument 82 c is directed by the surgeon from the surgeoninterface 250 (see FIG. 3A).

The internal mammary artery can be joined to the extended incision 914in the coronary artery 703 by a variety of conventional techniques,including suturing, laser welding, microstapling, and the like. It willbe preferred to use conventional suturing techniques as illustrated inFIGS. 15A-D. A length of suture 916 (see FIGS. 15A-D) has needles 918 ateither end, which are manipulated using the forceps 82 d attached to thesurgical manipulator 80 to join the free upstream end 910 of theinternal mammary artery 600 graft to the opening created by extendedincision 914 in the coronary artery 703.

After the suturing is complete, the internal mammary artery 600 will bejoined to the coronary artery 703. It is noted that prior to suturing,temporary clips (not shown) are placed upstream and downstream of theregion of the internal mammary artery to be transected. After suturing,the temporary clips will then be removed to permit blood flow into thecoronary artery 703, thus bypassing the previous blockage in thecoronary artery 703. The downstream free end of the internal mammaryartery will remain clipped as before. Following completion of thecoronary anastomosis, all heart manipulating devices (not shown) will beremoved from the patient, and the heart will be permitted to return toits natural orientation.

FIGS. 16 and 17 depict schematic views of a preferred embodiment of aretractor that can be manually manipulated by a surgeon's assistantduring a surgical procedure. This manually operable retractor comprisesa longitudinal shaft 756 coupling the distal end 782—preferablycomprising the stabilizer end effector 400 and the proximal and distaldevises 752 and 750—to the proximal, manually manipulable end 780. Asshown in FIG. 17, the proximal end 780 generally comprises aback-endclevis 760, pitch plate 766, and back-end grips, 762 and 764. Theback-end clevis 760 provides the interface between the back-end and theshaft 756. The pitch plate 766 rotates with respect to the back endclevis around axis 767 and is operatively coupled to the distal clevisso that its movement around axis 767 relative to the back-end cleviscauses substantially similar movement of the distal clevis 750 aroundaxis 754 relative to the proximal clevis 752. Grips 762 and 764 areattached to the pitch plate 766 and rotate with respect thereto aroundaxes 782 and 784 that are preferably substantially perpendicular to thepitch axis.

The elongate shaft or coupling tube 756 houses cable/hypotube assembliesoperatively connecting the proximal and distal ends of the apparatus.The shaft permits the distal end 782, which may be inside the body, tobe manipulated by the proximal end 780, which typically remains outsidethe body in a minimally invasive procedure. The right-hand grip 762 isoperatively coupled to the right-hand body 402; the left-hand grip 764is operatively coupled to the left-hand body 404. Each operativecoupling comprises a pair of opposed cable/hypotube assemblies fortransmitting movement at the proximal end to the apparatus' distal end,so that each body/clevis may move in opposing directions around itscorresponding pivot axis.

Although in the preferred embodiment, each body has a corresponding gripon the apparatus' proximal end, the manual controls may also comprise asingle member operatively coupled to both bodies 402 and 404 so thatmovement of the single member at the proximal end of the apparatus movesboth bodies relative to the shaft but not relative to one another. Thissingle member preferably would comprise an actuating mechanism foropening and closing the bodies relative to one another. With thiscombination of controls, the same functionality as that achieved by theproximal end of the embodiment shown in FIG. 17 would be achieved.

The proximal end 780 also includes tensioning disks 768 that are used tointroduce tension in the cable assemblies. Tension is typically providedduring the manufacturing process, so all motion in one grip, forexample, is transmitted to its corresponding distal body. Preferably, nomotion is lost due to looseness in the cables.

Locking mechanism, comprising lock nut 758, can be releasablymanipulated to prevent further motion of the cable/hypo-tube assembliesrelative to shaft 756. This locking mechanism may be constructed so thatthe user can partially loosen the nut and adjust one degree of freedomof movement of the end effector while maintaining at least one otherdegree of freedom of movement substantially fixed.

FIGS. 17A and 17B depict the locking mechanism 758 in more detail. Ascrew or threaded lever (not shown) is positioned within threadedchannels 792.1 and 792.2 and may be used to tighten the two joinedhalves of clamp 799 around the centrally located mechanism shown best inFIG. 17A. If a screw is used, the screw head is held in recess 791.Tightening clamp 799 in this manner causes pins 793 to force lockingplates 795 closer together, thereby increasing the friction between thelocking plates 795 and the hypotube/cable assemblies 797 and so holdingthe assemblies in place.

The compression of clamp 799 is released by releasing the screw orthreaded lever to allow the clamp halves to bias apart. Partiallyreleasing the clamp in this manner maintains friction on the cableassemblies to continue to hold them in place, but also appliessufficiently less friction that each degree of freedom of movement ofthe distal portion of the instrument may be independently manipulated byovercoming the remaining friction applied by the clamp. In this way, thepositioning of the instrument may be fine-tuned by manipulating (e.g.,only one set of cables) without having to reposition the entiremechanism in all its degrees of freedom of movement.

In use, this manual instrument control mechanism may be held by the useror attached with a frame to the patient or the operating table, tomaintain its position relative to the patient during the surgicalprocedure. For example, a positioning arm could attach to the rails ofthe operating table and a clamp could adjustably rigidly hold the shaftin position during the surgery. Preferably before clamping, theretractor 400 is straightened and inserted into the body through acannula. When inside the body, the tool is manually manipulated intoposition. The user—typically the surgeon's assistant—stands next to thepatient and watches the motion of the tool on a displayed image capturedby an endoscope, for example. All of the motion is preferably scaledone-to-one, so that the surgeon can learn the position of the retractorbodies simply by viewing the relative positions of the proximal grips.Once the tool is in position, the position of the tool is fixed relativeto the patient and the locking mechanism is tightened. Although thismechanism is disclosed in the context of a heart stabilizer, it hasapplication to control any surgical end effector with a wrist jointand/or three degrees of distal freedom of movement. For example, theapparatus could be used to position a forceps around a piece of tissue,and then have the forceps hold that tissue until manually maneuvered todo otherwise. The application of this manually adjustable apparatus thusshould not be understood as being limited to positioning a stabilizer.

FIGS. 18 and 18A illustrate a robotic tissue retractor 830 for use withthe system of FIG. 1. Retractor 830 includes first and second retractorelements 832, 834 which can be independently articulated, as describedabove. Each retractor element has at least one arm 836 with a bend 838so that the arms can each pull and/or push tissue normal to theretractor element. Preferably, two or more arms are provided on eachelement, with the tool typically having one, two, or more retractorelements.

In use, retractor elements 832, 834 may be spread apart and used toretract tissue from an internal surgical site as described. The arms 836of a first retractor element 832 may extend distally beyond bends 838 ofthe second retractor element 834 to avoid interference when the elementsare aligned in a small profile configuration for insertion and removal.The exemplary retractor elements comprise flattened hypotube crimped andglued around formed wire, such as 0.021″ diameter stainless. Theproximal ends of the hypotube may similarly be crimped and glued to endeffector elements of a microforceps or the like. Alternative retractorelements may comprise structures similar to those described in U.S. Pat.No. 5,613,937, the full disclosure of which is incorporated herein byreference.

Thus, while the present invention has been described herein withreference to particular embodiments thereof, a latitude of modification,various changes and substitutions are intended in the foregoingdisclosure, and it will be appreciated that in some instances somefeatures of the invention will be employed without a corresponding useof other features without departing from the scope of the invention asset forth. Therefore, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from the essential scope and spirit of the presentinvention. It is intended that the invention not be limited to theparticular embodiment disclosed as the best mode contemplated forcarrying out this invention, but that the invention will include allembodiments and equivalents falling within the scope of the appendedclaims.

What is claimed is:
 1. A tissue stabilizer comprising: a shaft having alongitudinal axis extending along a length of the shaft; first andsecond stabilizing bodies, wherein the first and second stabilizingbodies respectively have first and second tissue engaging surfaces,wherein the first and second tissue engaging surfaces are adapted toconcurrently engage and inhibit movement of a target tissue in a samedirection, surfaces, wherein the first and second stabilizing bodiesrespectively have first and second tissue non-engaging surfaces that arerespectively on opposite sides of the first and second stabilizingbodies relative to the first and second tissue engaging surfaces, andwherein the first and second tissue engaging surfaces have higherfriction surfaces than the first and second tissue non-engagingsurfaces; a wrist assembly coupling the first and second stabilizingbodies to the shaft, the wrist assembly configured with a first pivotdefining a first axis about which the first and second stabilizingbodies are pivotable together and a second pivot defining a second axisabout which the first and second stabilizing bodies are pivotableindividually, wherein the first and second axes are constrained byconstruction of the wrist assembly to be substantially orthogonal; andfirst and second grips operatively coupled through the shaftrespectively to the first and second stabilizing bodies for individuallypivoting the first and second stabilizing bodies about the second axis.2. The tissue stabilizer of claim 1, wherein the wrist assemblycomprises: a proximal clevis coupled to a distal end of the shaft, theproximal clevis having the first pivot; and a distal clevis coupled tothe proximal clevis at the first pivot so as to be pivotable about thefirst pivot, the distal clevis having the second pivot; wherein thefirst and second stabilizing bodies are coupled to the distal clevis soas to be pivotable about the second pivot.
 3. The tissue stabilizer ofclaim 2, wherein the proximal clevis is constructed to allow the distalclevis to pivot about the first axis so that angle between the secondaxis and the longitudinal axis of the shaft is less than ninety degrees.4. The tissue stabilizer of claim 1, wherein at least one of the firstand second stabilizing bodies has one or more vacuum ports.
 5. Thetissue stabilizer of claim 1, wherein no line that passes through and isnormal to the first tissue engaging surface passes through the secondtissue engaging surface when the first and second tissue engagingsurfaces are engaging and inhibiting movement of the target tissue. 6.The tissue stabilizer of claim 1, wherein the first and second tissueengaging surfaces comprises one of a more textured, more knurled, andmore roughened surface than the first and second tissue non-engagingsurfaces.
 7. The tissue stabilizer of claim 1, wherein the first andsecond tissue engaging surfaces comprises one of a higher frictionmaterial, higher friction coating, and higher friction adhesive than thefirst and second tissue non-engaging surfaces.
 8. The tissue stabilizerof claim 1, wherein the first stabilizing body has a first cleat formedon the first tissue non-engaging surface.
 9. A tissue stabilizercomprising: a shaft having a longitudinal axis extending along a lengthof the shaft; first and second stabilizing bodies, wherein the first andsecond stabilizing bodies respectively have first and second tissueengaging surfaces, wherein the first and second tissue engaging surfacesare adapted to concurrently engage and inhibit movement of a targettissue without the target tissue being held between, or separated by,the first and second tissue engaging surfaces, wherein the first andsecond stabilizing bodies respectively have first and second tissuenon-engaging surfaces that are respectively on opposite sides of thefirst and second stabilizing bodies relative to the first and secondtissue engaging surfaces, and wherein the first and second tissueengaging surfaces have higher friction surfaces than the first andsecond tissue non-engaging surfaces; a wrist assembly coupling the firstand second stabilizing bodies to the shaft, the wrist assemblyconfigured with a first pivot defining a first axis about which thefirst and second stabilizing bodies are pivotable together and a secondpivot defining a second axis about which the first and secondstabilizing bodies are pivotable individually, wherein the first andsecond axes are constrained by construction of the wrist assembly to besubstantially orthogonal; and first and second grips operatively coupledthrough the shaft respectively to the first and second stabilizingbodies for individually pivoting the first and second stabilizing bodiesabout the second axis.
 10. The tissue stabilizer of claim 9, wherein thefirst tissue engaging surface defines a first line that passes throughand is normal to the first tissue engaging surface when the first tissueengaging surface is engaging and inhibiting movement of the targettissue, wherein the second tissue engaging surface defines a second linethat passes through and is normal to the second tissue engaging surfacewhen the second tissue engaging surface is engaging and inhibitingmovement of the target tissue, and wherein the first and second tissueengaging surfaces are disposed relatively to each other so that thefirst and second lines are substantially parallel when the first andsecond tissue engaging surfaces are engaging and inhibiting movement ofthe target tissue.